On the Response of a Beam Subjected to a Cyclic Moving Load

A theoretical analysis is presented on the damped steady state response of a simply supported beam on an elastic foundation subjected to a cyclic moving load that oscillates longitudinally along the beam about a fixed point. Loadings of this type have been recently shown to yield an infinite number of load movement frequencies that will excite resonance of a given natural frequency of an elastic member or system of members. It is the purpose of this investigation to introduce damping into the problem in order to determine both the absolute and relative importance of this infinite number of load movement frequencies that will excite a given natural frequency of a beam. The mathematical analogy between the problem of a beam resting on an elastic foundation and that of a long circular cylindrical shell with axial and rotatory inertia neglected is noted. Hence the results obtained are applicable to either problem. Numerical results are presented to illustrate the effects of damping, frequency of oscillation of load movement and amplitude of load movement on the dynamic deflection of the beam.